Method of extracting values prom coal and like material



Sept. 8,1931. F. c. GREENE ET Al. 1,822,142

METHOD OF .EXTRACTING VALUES FROM COAL AND LIKE MATERIAL original Filed Feb. 21, 1918 s sheets-sheet 1 Sept. 8, 1931. l F, c. GREENE ET Al. 1,822,142

METHOD 0F EXTRACTING VALUES FROM COAL AND LIKE MATERIAL original Filed Feb. 21, 1918 s sheets-sheet v2 Sept. 8, 1931.

F. C. GREENE ET AL.

METHOD QF EXTRACTING VALUES FROM COAL AND LIKE MATERIAL Orginal- Filed Fb. 21,. 1918 5 She-ts-Sheet 5 Patented Sept. 8, 1931 UNITED STATES PATENT OFFICE FRANK C. GREENE AND IRVING F. LA'U'CKS,

0F SEATTLE, WASHINGTON, ASSIGNORS TO OLD BEN COAL CORPORATION, OF CHICAGO, ILLINOIS, A CORPORATION OF DELA- WARE METHOD EXTRACTING VALUES FROM COAL AND LIKE MATERIAL Application filed February 21, 1918,' Serial No. 218,452. Renewed April 11, 1927.

Coal has been dened by one well-known authority (V. B.` Lewes, in Carbonization of Coal"), as being a conglomeration of humus and its degradation products with resinic bodies and their derivatives. The present process is based upon the discovery that at relatively low temperatures and properly controlled pressures, these resinic and l hydrocarbon bodies and their derivatives can be more readily removed and more valuable byproducts obtained than heretofore.

T o the accomplishment of the foregoing and related ends, our invention, accordingly, consists of the steps hereinafter fully described and particularly pointed out inthe claims, the annexed drawings and the following description setting forth in detail one approved method of carrying out'the invention, such disclosed method, however, constituting but one of the various ways in which the p principle of the invention may be used.

In said annexed drawings z- Fig. 1 1s aside elevation of a suitable retort out our lmproved recovery partly a section of such pair of retorts; Fig. 3 shows a detail vof the furnace; and Figs. 4 and 4b, illustrate a transverse section of the retort, or rather a pair of such retorts, the plane of the section being different Vin the two retorts, respectively.

Ve do 'not concern ourselves with the coni flicting theories nor the acceptedtheories concerning the constitutionand thermal decomposition of various coals.

le are aware that many distillation processes and chemical reactions, including decomposition reactions, are greatly aiected by time, temperature, pressure, and con'entration. A carbonization process is likewise affected by all of these and hence in our process we assume that we have minimized one or more heretofore prominent reactions which 4 produce more paratlins than aromatics 1n the product.

The elements of time and temperature are well known factors involved in all coking processes. Some have used pressure increased or reduced from normal atmospheric conditions. We use reduced pressure which sults.

minimizes the concentration of the vapors temperature.

we reduce the time in which the material approaches the temperature of the zone through which it is'passing. By using line particles we reduce the time for each particle to become uniformly heated as well as permit the particles to be agitated or dispersed in and out of Contact with the heated walls of the retort. We also use a screw conveyer in a vertical retort to pass the charge of material continuously therethrough, the screw having radially horizontal ights upon which rests the thin layer of the material.

Heretofore, screw conveyers in retorts have been used, but the process has produced the usual plastic stage of coal which clogs the conveyer. Te can do the same with our conveyer by advancing the material too speedlly yinto the hotter zones, wherein certain of the coal constituents fuse and the plasticity re- However, we have found that slow advance, when distilled under vacuum, permits the removal of the more volatile constituents at a lower temperature so that the plastic stage is delayed, lessened, or even eliminated, to such an extent that clogging of the screw does. not result. By this process we remove the volatile matter of the coal in the form of oil and tar.

It will be understood, of course, that the present process is not based upon any particular theoretical considerations, such as have been expressed above, but'upon the results secured by following the prescribed steps. The illustrated apparatus lfor carrying out these steps, moreover, is to be taken as illustrative, it notbeing intended to imply that our improved method or process is limited to utilization in any particular form of apparatus.

In such illustrated apparatus vertical retorts 1 of general cylindrical form are.

utilized in which to heat the coal or like material. The latter is de'sirably finely ground, the minimum limit of fineness being determined by the conditions attending the handling of a powdered material of thischaracter, both in conveying it to the retort and in passing it through such retort. r1`he maximum limit is determined by the size of particle which will yield up the volatile products from its interior before the outer portion thereof reaches a temperature where a destructive edect will be had on the vapors escaping from the interior of the particle. We have in practice found it feasible `to work with particles from one-fortieth inch to one-half inch in diameter. The manner in whichl the material is reduced to the requi tion may make necessary. The retorts are preferably suspended from their upper ends, in the furnace chamber, so as to permit free downward variable expansion. rEhe combustion chamber 3, from which the gases for heating the retorts are derived, is conveniently located between the two furnace chambers, such heated gases entering the latter at the bottom through openings 4, as shown in Fig. 4b, and escaping at the top through openings 5 int-o a waste heat duct 6.

A lighting hole 7 leads from the exterior of the one furnace chamberto 'said combustionchamber, for igniting the combustible mixture of air and gas supplied to the burner 8 therein from air and gas mains 9 and 10, respectively. ylhe latter are simultaneously controlled by means of suitable valves 11 and 12 operated by means of a lever 13, likewise 'extending with-out the wall of the furnace chamber. A hole 14 is also provided in the A wall of each chamber near the bottom of the latter for the insertion of a pyrometer (not shown), in order to determine the temperature within such chamber.

Each retort, proper, consists of a vertically disposed tube, preferably of iron, which extends the length of the furnace, such tube being provided with external ribs 15 disposed in a helical fashion about `the same, that cause the combustion gases, as they pass upwardly throughthe furnace chamber, at the same time to circulate about the retort, and so insures the thorough and uniform heating of all portions of the same, and large absorption of heat.

Within each such tubular retort is rotatably mounted a second tube 16, the upper end of which projects beyond the upper end, not only of the retort proper, but of a head 17 that surmounts the latter. lnner tube 16 is flange 18, that extends from its lower end to a point adjacent the upper end of the retort,l

and is of a width to substantially span the annular space left between the tube and retort. Said inner tube is also provided, between the flights of such spiral rib, with a series of perforations 19, that permit and afford free communication for vapors to quickly escape from the annular space, between the retort walls and such tube, to the interior of the latter. The upper end of each such inner tube is closed by a vacuum seal consisting of a counter-weighted valve 20, that is held to its seat by the vacuum within the tube produced, as will be'presently described, but is adapted to open optionally upon the breaking of such vacuum. Driving means for rotating each tube are likewise connected with the upper ends thereof, such means consisting of a ratchet wheel 21 operated by a pawl 22 on an oscillatory arm 23, the free end of which engages a cam 24 on the main drive shaft 25 of the apparatus. To reduce power required for rotating tube 16, a suitable ball-bearing 1617 is employed under the upper bearing-flange 16a in the head 17.

The upper portion of the head 17, that surmounts each retort is sealed off by means of'a suitable flange 26 from the lower portion thereof, which latter freely communicates with the retort, that is, with the annular space between the inner tube 16 and the retort walls; while above the partition, provided by such flange, other perforations 27 are formed in said inner tube, by means of which its interior is connected through a duct 28 with a vapor main 29, that is placed under suction by means not shown, and the desired degree of vacuum thus provided within the tube. A valve 30 is provided in each duct 28 for closing the same simultaneously with the opening of a discharge gate 31 at the bottom of the char chamber 32, and vice versa, as will be presently. described.

Connected with each head 17, below the partition 26 therein just referred to, is a duct 33 that is adapted to receive the finely ground coal, or like material, from a conveyer trough 34 and supply the same to the upper end of the retort. The rate of feed is controlled by means of a screw 35 located intermediate between the ends of such duct, this screw being connected to be operated from the drive shaft 25 by means of achain 36 and suitable variable speed gearing 37, which need not be described in detail. A valve 38 for closing the duct 33 is also provided, such valve being interconnected with the valve 30 in the corresponding vapor duct by a link 39.

The lower end of each retort communicates with, and discharge directly into, the char chamber 32 abovereferred to, that is located directly therebencath. The lower end 55 provided externally with a spiral `rib or of such char chamber in turn is adapted to be sealed by means of the discharge gate 31, likewise referred to above, attached at one side of the chamber and normally held closed by means of a swinging yoke adapted to engage therewith through the medium of a roller 41 and tightly close the same as it'is swung from the position indicated in dotted lines, to that indicated in full lines, in Fig. 4".

As previously indicated, the operating means for this discharge gate, consisting of the yoke just described, areinterconnected with the valve 30 in the corresponding vapor duct 28 at the upper end of the retort, the rod 42, that serves for this purpose, extending Well above the retort and serving, when raised, -not only simultaneously to close the discharge gate in question and to optionally open the valve in the vapor duct, but also, through the link 39, to open the valve in the feed duct, and, through the medium of a projection on its upperv end, to optionally lift the weighted arm of the valve 20 that closes, or seals, the upper end of the inner tube of the retort.

In addition to provision being made for the withdrawal of vapors from the interior ot" the inner tube of the several retorts, a second vapor main 45 is disposed alongside the lower ends of the series of retortsl and is connected with the upper portions of the corresponding char chambers through suitable ducts 46 that are controlled by valves 48 operatively connected with the rods 41, just as are the valves in the upper ducts. We also provide in this connection a plston or stopper 50, that is adjustably fitted within the lower end of each inner tube, being of expansible construction,

so that it may be locatedwhere desired by means of a rod 51 depending therefrom into the char chamber, and by rotation of such rod caused to frictionally seat itself in such selected location. The location of this piston, or stopper, will obviously determine the point at, which, in the descent of the material through the retort, the vapors given olf therefrom are conducted upwardly and collected in vapor main 29, and the point at which the vapors thus given off are conducted downwardly and collected in the lower vapor main 45.

The charred or carbonized residue, upon being discharged from chambers 32, is received and collected in a receptacle of ade-- quate size, the side walls of which converge towards a trough-like depression 55 in which an endless belt 56 or other conveyor operates to transfer this material to any desired point.

Having regard to the illustrative apparatus just described, the manner of operation, exemplifying our improved method or process for extracting values from coal and like material, may now be briefly set forth. The suitably crushed, and preferably dried, material is received in the upper end of the` that is pivotally retort, or rather into the upper end of the annular space between the rotatable inner tube in such. retort and the inner wall of the latter, from the conveyor through the feed duct 33. The feed screws 35 in such duct serves to regulate the rate of feed.

The rate of feed is regulated so as to supply the material in a stream of suitably adjusted quantity on the spiral ange 18 carried by the rotating inner tube. The material, in other words, is passed through the retort in the form of a relatively thin vertical (in this case) layer resting on this amounts to a continual turningoverof the layer. This action is important as tending to expedite and facilitate the evolution of vapors and their ready withdrawal, constituting an effect similar -to dispersion. mode of supplying the 4heated gases to the furnace chamber, taken in conjunction with the. arrangement o-f ribs 15 on the retort insures an equable heating effect and absorption of heat in all horizontal planes, althoughl the` heating gases are of course hottest in the lower portion of the furnace chamber and graduallyy cool ofi' as they ascend vertically,'

due to the absorption of heat by the material as it passes downwardly through the retort. A'higher temperature may be used in the lower section of the retort to drive olf-all volatile matters from the `material being Thel treated, and thus approximate known coking processes.

Additional burners may be applied to the retort l at various points along its length to provide heat to a degree commensurate with the absolute pressure` iineness and composition of the coal or like material, and speed of operation of expansion of evolved vapors,

Externalheating temperatures may thus be varied, as may pressures, speed, ineness. Such temperatures we have found may vary from say 800o Fahr. to 1200o Fahr. although these limits are not fixed. Apparently the limiting element of this operation is the reduction of pressure to a perfect vacuum, which, while practically unobtainable, is the desideratum. Provision is made for tightly sealing the retort at both ends, and,by means of suitable suction apparatus connected with the two vapor mains, we reduce the pressure within the retort to the lowest possible employed, `and with the degreel degree, an increase in the pressure towards atmospheric resulting in a corresponding decrease in the amount of aromatic oils in the products obtained.

The suction thus employed in order .to reduce the pressure within the. retort is simultaneously effective to Withdraw the vapors, as fast as they are formed, away from the heated zone; that is. they are sucked through the apertures in the inner vapor tube and thence to suitable collecting and condensing apparatus, such vapor tubel being found to have a considerably lower temperature under these conditions, by at least several hundred degrees, than the external heating temperature.

lVhere it is desired to drive olf all the volatile constituents possible by applying to the lower portion of the retort a higher range of temperature than that indicated above, the use of a piston or stopper Within the vapor tube is desirable. since in lthis way it is rendered possible to segregate the so-called lean gases resulting from this stage in the process, from the vapors, which are evolvedv in the initial or main stage of the process. In other Words, by the means in question ive are enabled to effect a fractional distillation of the volatile constituents in the original material.` Such fractionating may be carried further if desiredfor We have found that,

by proper manipulation of the temperatures Within the retort and vapor tube, the vapors given oif may be made to consist more largely of either low-boiling or high-boiling com" pounds as desired.

tube varied from 480 to 300o F. and the vacuum from 14 to 22 inches respectively. The above charge results in 20.25 pounds of crude tar which analyzed to be 10.25 pounds of Water-free tar. The Water-free tar upon further distillation yielded the product as shown in the table above.

Other modes of applying the principle of our invention may be employed instead of the one explained, change being made as regards the methods herein disclosed, provided the step or steps stated by any one of the following claims or the equivalent 0f such stated step or steps be employed.

We therefore particularly point out and distinctly claim as our invention A process for extracting hydro-carbons and products of decomposition from coal comprising crushing the coal, passing the coal out of substantial contact with air in a thin spiral stream' through a zone of gradually increasing temperature suflicient to produce substantial decomposition of the coal,

and subjecting the particles of material to a continuous rolling action during their passage through the zone.

Signed by us, this 14th day of February,1

FRANK C. GREENE. IRVNG F. LAUCKS.

A comparison of the yields obtained by any Y y such current process of coal distillation with those obtained in the actual practice of our process, will substantiate the foregoing. Thus We have found that a coal having the following percentage composition, when analyzed in the usual Way, viz., moisture 1.67, volatiles 37.02, fixed carbon 51.19, and ash 10.12, produces, besides a quantity of gas, as follows:

Lbs.' actual Per cent per 100 lbs. Lbs. per

in tar coal ton coal Benzol .2.61A 0.23 4.6

Toluol 1.48 0.137 2.82 Solvent naphtha 3.66 0.38 7.6 Phenois 6.00 0.62' 12.4 Heavy oils 37.00 3.80 76.0 Pitch 49.25 Y 5.025 100.5

y Total 100.00 i 10.192 203.92

In securing the results tabulated above, it should be further explainedthat 100 pounds of finely divided coal (crushed in a jaw-type crusher so as to pass all through a one-half inch screen) Was treated in an apparatus of the type hereinbefore described for a total period, approximately. four hours, during which the temperature inside of the vapor 

